biodiversity

Question 1

what is biodiversity

Answer 1

the number of different ecosystems and habitats in an area, the number of species within those ecosystems, and the genetic variation within each species

Question 2

what is a specie

Answer 2

a group of organisms of common ancestry that interbreed to give rise to fertile offspring

Question 3

name an example of an ecosystem that has a high biodiversity

Answer 3

tropical rain forests or coral reefs

Question 4

name an ecosystem with a low biodiversity

Answer 4

surface waters in open oceans, sand dunes, recently ploughed fields etc

Question 5

occurring to Rio convention definition, biodiversity is considered on 3 levels

Answer 5

• the different ecosystems and habitats present in an area
• the different species present in the same area
• the genetic variation within each species

Question 6

there are several ways to assess the genetic diversity in a population. These include assessing

Answer 6

• the proportion of gene loci that have two or more alleles (gene variants)
• the proportion of the population that are heterozygous for any particular gene loci
• the number of different alleles for certain genes

Question 7

what is a habitat

Answer 7

a place where a species lives, expressed in one or a few words; for example, pond, lake, river, coral reef etc.

Question 8

what is a niche

Answer 8

The role of a species in an ecosystem; for example its position in the food web. A niche includes a description of all of a species interactions with the different factors in its environment

Question 9

what is species richness

Answer 9

the number of species present in an area

Question 10

what is species evenness

Answer 10

a measure of the relative abundance of the different species in an area

Question 11

what are the two types of quadrats

Answer 11

• an open frame quadrat
• a gridded quadratic
• much larger quadrats, that can be marked out with tape or by using GPS to pinpoint their location

Question 12

what are quadrants used for

Answer 12

a standard piece of apparatus for assessing the abundance

Question 13

what does high species evenness show

Answer 13

a high biodiversity

Question 14

quadrats can be used to assess abundance in several different ways by;

Answer 14

• species frequency
• species density
• percentage cover

Question 15

why must random sampling occur

Answer 15

to avoid any bias on the part of the person doing the sampling

Question 16

how can random sampling be done

Answer 16

by placing tape measures at right angles to each other along two sides of the sample area.
Random numbers are generated by using an app on a mobil phone to give coordinates where the quadrats can be placed

Question 17

often it is impossible to use quadrats to sample the animals. Some other pieces of apparatus are

Answer 17

beating trays 
pooter 
sweep net 
pond net 
pitfall traps

Question 18

what is a beating tray

Answer 18

a large white sheet is placed on the ground or supported by struts and held below a tree

Question 19

how to estimate a population size

Answer 19

number in first sample (S1) X num. in second sample (S2)
/
number pf marked in second sample (S2)

Question 20

sometimes random sampling is not possible or takes too long. Under these certain circumstances, it may be appropriate to carry out non-random sampling. This might be done in 3 ways by

Answer 20

• opportunistic sampling
• stratified sampling
• systematic sampling

Question 21

what is opportunistic sampling

Answer 21

what is available at the time the study is carried out and fit the criteria your are looking for

Question 22

what is stratified sampling

Answer 22

sampling method which is representative to the population in the area of the study
for instance if 10% of the area is occupied by open verges, then 10% of the sample method should be taken in this habitat

Question 23

what is systematic sampling

Answer 23

The process of systematic sampling typically involves first selecting a fixed starting point in the larger population and then obtaining subsequent observations by using a constant interval between samples taken.

• the best way to sample areas like this is to use a transect, which is a line placed across the area sample. A transect is used two different ways
• line transect
• belt transect

Question 24

what is a line transect

Answer 24

simply a straight line marked out across a habitat

• the choice of where to start the transect should be chosen randomly
• the species which touch the line intervals (every 0.5m) are identified and recorded.
• the results are converted into a drawing that shows the distribution of organisms
• line transects are used to show how communities change along a gradient, which could be a slope or a change in an abiotic feature.

Question 25

what is a belt transect

Answer 25

is a quantitative way to sample an ecosystem - involves along quadrats along a line taken through an ecosystem - if the distance is short then the quadrats can be placed back to back continuous belt transect - if the distance is long then the quadrats can be placed at intervals, interrupted belt transect